Now that LeBron James and the Miami Heat are 2012 NBA Champions, the talk surrounding a repeat can begin.

The way the Heat dominated the Oklahoma City Thunder in the 2012 NBA Finals certainly makes the thought of repeat championships realistic.

With that being said, if the Heat thought teams were gunning for them this season, they'll be in for a rude awakening next year—when the 29 other NBA teams will be trying to dethrone the champs night in and night out.

Ahead are seven teams that could keep LeBron James and the Miami Heat from winning back-to-back championships and creating the next great NBA dynasty.

Honorable Mention: Cleveland Cavaliers

This one might seem like a bit of a stretch, and that's why the Cavaliers are listed as an honorable mention here.

A LeBron James vs. Cleveland storyline would be great for the NBA, and with the Cavaliers gaining some steam heading into next season, it's certainly not all that impossible.

With Kyrie Irving leading the way, the Cavaliers have quite an opportunity with their four picks in the 2012 NBA draft to quickly transition from being a team with a lot of potential to being a legitimate playoff team in the Eastern Conference.

If the Cavs can land a player like Bradley Beal and form a productive backcourt duo, they'll certainly be a competitive team next season.

As long as LeBron is playing for the Heat and trying to establish the next great dynasty in the NBA, his hometown Cavaliers will always be in the back of his mind.

If they can continue to add talent to their roster, they might very well be able to compete in the East next year.

7. Milwaukee Bucks

Yes, I know the Milwaukee Bucks didn't make the playoffs last season, finishing with an underwhelming 31-35 record.

But that doesn't mean they won't be able to contend in the Eastern Conference next season.

The Bucks were one of a few teams to win their regular season series with the Heat last season, including beating the Heat on the road, and they did so with impressive play from Brandon Jennings and the frontcourt toughness of Ersan Ilyasova and Drew Gooden.

Now that the Bucks have Monta Ellis in the backcourt with Brandon Jennings, they'll be able to compete even more with the Heat and their big three.

With the No. 12 pick in the 2012 NBA draft, the Bucks have an incredible opportunity to find a franchise center and quickly become a legitimate team in the East.

6. New York Knicks

The 2011-12 season didn't exactly end the way the New York Knicks wanted it to, but that's all the more reason to believe that they'll come back firing on all cylinders next season.

With another offseason for Carmelo Anthony, Amar'e Stoudemire, Tyson Chandler and the unnamed point guard of their future to build chemistry, the Knicks should, in theory, be a force to be reckoned with next season.

If the Knicks can find a few role-players to compliment their core talent, the Knicks can certainly give the Heat a run for their money because they have one thing the Heat struggle with—legitimate frontcourt play.

If the Knicks, led by head coach Mike Woodson, can find the chemistry that's eluded them last year, the Heat will have a new rival for the top spot in the Eastern Conference.

5. L.A. Lakers

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As long as Kobe Bryant is wearing a Lakers' jersey, the Lakers will be a competitive team not only in the Western Conference, but across the league.

While the Lakers split their regular-season series with the Heat this past season, with their one win coming with Chris Bosh not on the court, there's no doubt that with Andrew Bynum on the roster they'll always stand a good chance at competing with the Heat.

If the Lakers can manage to find a scoring point guard this offseason, they'll certainly be a formidable opponent for the Heat, even if finding that point guard involves trading away a player like Pau Gasol.

A Lakers vs. Heat rivalry would be an interesting one to see because it would finally give NBA fans the LeBron vs. Kobe playoff/finals series they've always wanted to see. Can Kobe rise to the occasion and get in the way of LeBron and back-to-back championships?

4. Indiana Pacers

It wasn't that long ago that the Indiana Pacers were up two games to one on the Miami Heat in the Eastern Conference semifinals.

Just when it looked like the Heat may have met their match, LeBron James stepped up his game and began his journey towards his first NBA title.

While the Heat were able to hold off the Pacers this past postseason, the Pacers aren't going anywhere, and they'll certainly only get better with more time together as long as they're able to bring back the talent they have on their roster.

Retaining young talent like George Hill and Roy Hibbert is key to contending with the Heat next season. And if they can utilize their No. 26 pick in this year's draft to add scoring to their second unit, they'll be a team that could keep the Heat from winning a second-straight NBA title next season.

3. San Antonio Spurs

Assuming Tim Duncan re-signs with the San Antonio Spurs, the Spurs will be one of the best teams in the NBA next season.

Not only is their roster full of veteran talent, but they're also one of the best coached and most fundamentally sound teams in the league.

If there's one thing we learned about the Heat this past season, it's that they struggle against teams that know how to move the ball, solidify their offense in the paint and play legitimate half-court offense.

That's exactly the kind of team the Spurs are, and that's why the Spurs could keep the Heat from creating a dynasty in the NBA. It's age before beauty with the Spurs, and that certainly works for them.

There's no doubt that Gregg Popovich will have the Spurs ready to compete again next season, which could include an NBA Finals appearance against the Heat.

1. Chicago Bulls

It should come as no surprise that the Chicago Bulls are at the top of the list of NBA teams that could stand in the way of a LeBron James and Miami Heat dynasty.

Even without Derrick Rose for a few months, the Bulls have enough talent to remain competitive in the Eastern Conference, mainly because they have one of the deepest benches in the NBA.

The Bulls also have a legitimate frontcourt presence, with Taj Gibson, Carlos Boozer and Joakim Noah, and that's something that the Heat struggled with throughout this past season.

Once Rose returns to the court, the Bulls will quickly return to being one of the top teams in the East, if not in the entire NBA.

If the Bulls are able to either draft or sign a legitimate shooting guard this offseason, they'll undoubtedly be able to be a complete team capable of going toe-to-toe with the Heat and keeping them from creating the next great dynasty in the NBA.